Mouse hack 4 sensors

[daewoomofo]

I'm working on integrating my Wico trackball into my MAME cabinet with a mouse hack.  The only ball mouses I could find have 4 optical sensors in them.  Has this been done before?  I have some pics so you everyone can see what I'm working with.





Which contact points do I use to connect to the trackballs optics?  As always thank you and any help offered is greatly appreciated.

[PL1]

Can you post a pic of the back of the PCB?

Hard to convey where to tap in on that PCB unless we can see the traces.   

Ball mice and trackballs work the same way -- two LED emitters paired with two sensors per axis, each sensor has its own data line, the rotary encoder translates changes in the highs and lows on the two data lines to determine which direction that axis is moving.

Coding for clockwise rotation
Phase  A   B
1         0   0
2         0   1
3         1   1
4         1   0



Based on other mouse hacks I've read about, the pinkish components are probably the emitters and the clear ones are probably the sensors.


Scott

[daewoomofo]

I should have though to post a pic of the other side of the board. I'm familiar with the the traditional mouse hack works, I researched it and when I got these two mouses I was a bit confused.  Each emitter and each receiver has two contact points on it. 



Thank you for your help!

[pbj]

Why not break out the soldering iron and try a few combinations until you find one that works?  You've spent more time posting about it than actually trying to figure it out would have taken.

 

[lilshawn]

the black ones look like the emitters...mainly because they are all tied together. the red ones look like they go to the chip for decoding.

you can double check by firing up your digital camera and having a look at the sensors/emitters..... the emitters will show up as a purple or red light through the digital camera. the senstors won't be doing anything.

[nitrogen_widget]

I've got a used trackball from ebay coming & plan to do the same thing with a mouse also.

[daewoomofo]

I understand the mouse hack, its the fact that there is 2 emmiters and 2 receivers per encoder wheel that has me  scratching my head.  I dont want to just start connecting things together until I know what goes where, as tough of a time as I had finding these things locally I dont want to mess them, my trackball or my computer up.   Thank you for the digital camera trick.

[nitrogen_widget]

Can you take a dead on shot from above pic and not draw directly on the pads.

I tried to follow the traces from the pic you posted & it looks like  that second set of sensors are redundant but I can't tell for sure because of the angle & circles.

Oh and my imperial 3" trackball came in coincidently.
$10+$5 shipping & it looks pretty clean inside.
minor pitting on the rods that some ultra fine some steel wool mostly took care of.
Bearing's probably need replacing though as it's a bit noisy but still feels smoother than some golden tee machines i've used in bars.

[DaOld Man]

Most ball mice have dual sensors in each wheel (2 sensors in one chip). 2 sensors X 2 chips = 4 sensors.
This is how it detects direction (see PL1's post above).
Im not 100% sure, but it looks like they used two single sensors to accomplish the same feat as one dual sensor would do.
If this is true, you will need to wire to each sensor, with the wire connected to both probably being +5vdc.
If I am right, it will be simple. Just treat the two sensors (also know as receivers), as 1 dual sensor.
Remove both sensors, tie your trackball wires to one leg of each sensor (don't use the legs that are connected together, unless it needs to connect to the trackball, I cant remember, need to look it up.)
I know there is one or two chips that will not work as a trackball hack because they look for the receivers switching the ground instead of +5volts. (I think. This was discussed in a post a few years ago, I will see if I can find it.)

Edit: My posted link refreshed my old mind. The chip that will not work is looking for the receivers switching ground and positive to the chip. I guess the chip uses the serial pulses (positive or negative) the same as a trackball (and most mice) use 2 positive pulses.
Follow the traces on your circuit board. It looks to me like one leg of each sensor goes back to the chip. The other leg of each sensor are tied together and most likely to +. (See if there is a capacitor wired to this trace, it will probably be the + side of the cap wired to the trace.)
If you have a DVMM, power up the board and see if you have +5VDC to ground on this bus. (Ground is probably the thick trace wrapping around the outside edge of the board.)

[DaOld Man]

Heres the link to that thread.
Looking at your pictures, I think your mouse will work as a hack (no guarantee).

http://forum.arcadecontrols.com/index.php/topic,72265.msg744474.html#msg744474

[DaOld Man]

One more note, judging from how they are wired,  it looks to me like the black circles are the emitters, and the red circles are the receivers.
Emitters (circles in black) are hooked together in series, with a resistor in there too, and tie back to ground and the +5 volt bus that is on the receivers.
Emitters are powered on all the time. And this looks like how the black circled devices are wired, IMHO.

I don't see any problem with using this as a mouse hack, looks pretty simple.